I am driving a '99 Ram with an automatic transmission. I noticed today that it has begun to skip second gear by going directly from 1st to 3rd gear in the 'Drive' position. If I start out with the selector in 2nd, it never shifts out of 1st gear. Other than this oddity, I witness absolutely no irratic behavior or noises. It has a good solid and smooth feel at all speeds. To be safe, I just take it easy and let the engine slowly glide up to 2000-2500 RPMs before it gently shifts into 3rd, and then I can go from there. Does anyone have any ideas what may cause it, what I should look for, or what $$$ I should be prepared to pay for?

Thanks!